T-N.T. Studio APS-X HOP-UP System H+ Retrofit Kit for GHK M4 GBBR (370mm) [Code: APXINU-PB-2-0027]
Retail Price: 126.99
The T-N.T. hop up retrofit kit for the GHK M4 GBBR is a premium upgrade over the stock ones found in the out of the box guns listed. The kit ensures better accuracy due to better and finer tuning of the hop up.